Abstract The aim of this study was to identify the main sources of fecal pollution at popular beaches and rivers in the island of Trinidad. Escherichia coli enumeration and microbial source tracking (MST) were used to identify the primary sources of fecal bacteria contamination at the sites. Nineteen sites exceeded USEPA water quality standards for safe recreational use. Highest levels of fecal contamination were recorded on the central and west coasts of the island and included Brickfield River (4,839 MPN 100 ml−1), Orange Valley Bay (2,406.6 MPN 100 ml−1) and Chaguaramas Bay (1,921.2 MPN 100 ml−1). MST detected human (HF183) fecal pollution at ∼63%, birds at ∼67%, chicken at ∼36% and cattle (BacCow) at ∼34% of the sites. MST is a useful and rapid method for identifying major sources of fecal pollution in rivers and beaches. In Trinidad water bodies, the main sources of fecal pollution were humans and birds. The large number of sites with elevated levels of fecal pollution detected is particularly alarming and represents a serious public health risk. This article has been made Open Access thanks to the generous support of a global network of libraries as part of the Knowledge Unlatched Select initiative.

Seven villages in southeastern Kenya surround Mt. Kasigau and depend on the mountain's cloud forest for their water supply. Five of these villages have regularly experienced water shortages, and all village water supplies were contaminated with Escherichia coli bacteria. There is a need to economically find new sources of fresh ground water. Remote sensing offers a relatively quick and cost-effective way of identifying areas with high potential for ground water development. This study used spectral properties of features on Landsat remote sensing imagery to map linear features, soil types, surface moisture, and vegetation. Linear features represented geologic or geomorphologic features indicating either shallow ground water or areas of increased subsurface hydraulic conductivity. Regarding soil type, black soils were identified as potential indicators of shallow aquifers based on their relatively lower elevation and association with river valleys. A vegetation map was created using unsupervised classification, and three of the resulting vegetation classes were observed to be commonly associated with wet areas and/or ground water discharge. A wetness map, created using tasseled cap analysis, was used to identify all areas of high ground moisture, including those that corresponded to vegetated areas. The linear features, soil type, vegetation, and wetness maps were overlaid to produce a composite that highlighted areas with the highest potential for ground water development. Electrical resistivity surveys confirmed that areas highlighted by the composite image had relatively shallow depths to the water table. Some figures in this paper are available in color in the online version of the paper.

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A wetland system made up of linked basins was investigated to determine its role in local flood control and contaminant filtration. The study focused on a wetland basin that is dominated by the Celtis laevigata plant and is underlain by clay, with a small sandy layer approximately 1 m below surface. Field and laboratory data were collected to understand the transport and filtration of phosphate, iron, and nitrate. Field results showed the wetland to effectively reduce iron and phosphates from runoff via groundwater flow. These results also showed an increase in the phosphate concentration of surface water while within the basin, resulting from agitation of wetland sediments. Laboratory column experiments showed more than 90% reduction in phosphorus and iron while nitrate concentrations increased above the input concentration. Phosphate and iron were high in wetland water immediately after a rain event. Nitrate concentrations increased as the water filtered through the sediments due to desorption of previously adsorbed nitrates. This wetland could potentially act as a temporal hot spot and rain events as hot moments for these substances. Therefore, the best flood control measure for this site would be to increase residence time in the wetland. This would help to better manage/control the concentration of phosphate, iron and nitrate pollution in surface waters.

Bushland is a vegetation type with a dense cover of woody plants of low stature and a grass understory. We explored the influence of environmental factors (precipitation, topography, geology, hydrology and waterhole density) and historical land use in the Tsavo ecosystem bushland. We mapped vegetation patterns in the region using remote sensing, GIS and field data and tested relationships with physical factors. We used regression analysis to explore the interaction of physical factors and human influence by including a protected and a nonprotected area, representing contrasting historical land use policies, as factors in the regression model. Bushland vegetation had the largest proportion in the region as a whole, but its proportion was notably greater in the nonprotected area. Precipitation, elevation, geology and historical land use were significant predictors of vegetation patterns in the regression models. Higher precipitation and elevation make woody plants superior competitors over grasses, resulting in predominance of bushland in such areas. Geologically, marine deposits result in shallow calcareous soils that favour grasses over trees, hence, absence of bushland. Wildlife management policies such as providing water for wildlife, protective boundaries and controlling wildfires influence distribution of wildlife and result in conditions that prevent regeneration and recruitment of trees.